| 摘要 |
1323763 Zero suppression MOHAWK DATA SCIENCES CORP 15 Oct 1970 [15 Dec 1969] 49118/70 Heading G4H In a high speed printer, selectively controllable zero suppression circuits 20a-20n are provided, to prevent the printing of unwanted zeros. Data to be printed is fed to store 6 and then to a series of buffer registers 8a-8n each controlling one column of print. The data then passes to zero detectors 9a-9n and comparators 10a-10n. The other input of comparators 10a- 10n is supplied from a counter 13 which is incremented by the output of a magnetic clock pulse generator driven by the print drum 1. The counter is reset by a pulse produced once per revolution by the clock pulse generator. When agreement is obtained between the inputs of comparators 10a-10n the stored data to be printed agrees with the character on the print drum in the print position, and the print hammers are actuated via AND 16a-16n and drivers 3a-3n. AND gates 16a-16n are inhibited on alternate clock pulses via inverter 19 to permit the paper to advance. The AND gates 16a-16n may also be inhibited on lines 28a-28n by zero suppression circuits 20a-20n. Zero suppression.-The output of zero decoders 9a-9n which detect the presence of print zero data in buffer register 8a-8n, is fed to AND gates 20a-20n. If zero suppression is not required in particular columns, appropriate ones of contacts 25a-25n are closed, inhibiting the appropriate AND gates 21a-21n via inverters 26a-26n. If contact 25a is open and a zero is indicated on line 11a an inhibit signal is applied to AND gate 16a on line 28a, and an enabling pulse is supplied via OR gate 23 to AND gate 21b. Thus for zero suppression to be produced by circuit 20b either a zero must be present on line 11a or contact 25a must be closed inhibiting the operation of the preceding zero suppression circuit 20a. Successive zero suppression circuits 20c-20n operate in a similar manner. (For Figures see next page.) |
